The polar atmosphere is often considered both pristine and simple. However, there is a strong dynamic between the lower atmosphere and ice surfaces. Over the polar plateau, production in the snowpack controls the chemistry of the lower atmosphere. Halogen chemistry over the sea ice zone depletes boundary layer ozone, and causes mercury deposition. Persistent organic compounds undergo a distillation which leads to their deposition in polar regions. Biochemical processes in open leads play a major role in formation of cloud condensation (CCN) and ice forming nuclei (IFN), and through cloud formation this process may play a vital role in ice-albedo climate feedbacks. The IGBP projects, IGAC and SOLAS, have jointly endorsed a task, “Air-Ice Chemical Interactions”, to determine the importance of these processes, and assess how they would alter with a warming climate and shrinking cryosphere. IPY offers a unique opportunity to determine the spatio-temporal pattern of chemistry and processes from the ice surface through the boundary layer, including cloud formation, by linking various field activities carried out in the same year. AICI-IPY will provide an overall framework, arrange supporting laboratory and modelling studies and integration of remote sensing data, and organise synthesis meetings. This work will support and link these more focussed field activities: Polar plateau intensives: studying the influence of the snowpack, and boundary layer structure, by measuring concentrations, fluxes and processes at sites with different characteristics. Summit, Greenland has a long pedigree in air-snow studies, and this will be extended under AICI-IPY. The ANTCI group at South Pole expect to carry out further campaigns in IPY. AICI-IPY scientists will aim to add activities at Concordia (Antarctica). The Arctic Summer Cloud-Ocean Study (ASCOS) will focus on the processes that control boundary layer clouds north of 80ºN, looking at CCN, IFN, and investigating marine biochemical and boundary layer meteorological processes that control their numbers. ASCOS expects to use the Swedish icebreaker, drifting from North Pole during summer 2007, and this will provide opportunities for synergy with other parts of AICI and related projects. In the sea ice zone, both Arctic and Antarctic studies of gas phase chemistry are planned. The Arctic studies will mainly be hosted by the related project, OASIS (Ocean-Air-Sea Ice-Snow Interactions – EoI 344). OASIS contains ambitions both wider (biogeochemistry) and narrower (Arctic ocean/coast) than AICI, and will submit a separate detailed plan to IPY. POLARCAT (EoI 244) will provide some vertical context in the Arctic through aircraft campaign. Counterpart Antarctic coastal studies are already planned in Dronning Maud Land. To provide an overall context for the intensive campaigns, AICI-IPY will determine the year-round spatial distribution of at least that most important molecule, ozone, in the boundary layer. No picture exists of the scale of ozone production and depletion, and its concentration in the boundary layer is not amenable to satellite observations. This work will link other AICI studies, using sensors deployed on autonomous platforms and buoys. AICI will coordinate individual polar operators to fill gaps on the map in the Antarctic and over Arctic land, while OASIS will cover parts of the Arctic Ocean.